The first recorded fruits of this initially unexpected and seemingly improbable but by now well-established collaboration arrive over five years after contemporary jazz piano great Brad Mehldau and ‘King of the Mandolin’ Chris Thile made their stage debut as a duo during Mehldau's residency at the Wigmore Hall in London in 2011. Since then, they've toured together (in 2013) and reunited at the Bowery Ballroom in New York (in 2015) shortly before finally heading into the studio. The material here – a mixture of originals and covers spread across two CDs – doesn't stray too far from the template hammered out on stage: the inclusion of versions of tunes by Joni Mitchell, Bob Dylan and Elliott Smith on this self-produced set won't upend the expectations of attendees of the jazz/bluegrass duo's gigs. At least as important, they won't disappoint them either. As live reviewers have noted, these virtuosi of their respective instruments have the happy knack of driving one another to sympathetic fresh heights rather than sounding as though they're competing in a cutting session. Thile's gently raspy vocals set the emotional tone (folky singer-songwriters provide much of the non-original material), and his dazzlingly fluent, highly percussive mandolin work prove a wonderful foil to Mehldau's sensuously full piano work.